1869 to 1870 A.D. under Pope Blessed Pius IX
The 20th of 21 Ecumenical Councils
FIRST DOGMATIC CONSTITUTION
ON THE CHURCH OF CHRIST
Published In The Fourth Session
Of The Holy Ecumenical Council
Of The Vatican.
Pius Bishop, Servant Of The Servants Of God,
With The Approval Of The Sacred Council,
For An Everlasting Remembrance.
The Eternal Pastor and Bishop of our souls, in order to continue for all time the life-giving work of His redemption, determined to build up the Holy Church, in which, as the House of the living God, all who believe might be united in the bond of one faith and one charity. Therefore, before he entered into His glory, He prayed to the Father, not for the Apostles only, but for those also who through their preaching should come to believe in Him, that all might be one, even as He the Son and the Father are one. (John 17:21). Then He sent the Apostles, whom He had chosen for Himself from the world, just as he Himself had been sent by the Father. So did He will that there should ever be pastors and teachers in His Church to the end of the world.
And, so that the Episcopate also might be one and undivided, and so that, by means of a closely united priesthood, the multitude of the faithful might be kept secure in the oneness of faith and communion, He set Blessed Peter over the rest of the Apostles. And He fixed in him the abiding principle of this two-fold unity with its visible foundation, by the strength of which the eternal Temple would be built up, and the Church, in the firmness of that faith, would rise up, bringing her sublimity to Heaven. 
And since the gates of Hell, with greater hatred each day, are rising up on every side, to overthrow, if it were possible, the Church and Her divinely-established foundation, We, for the preservation, safe-keeping, and increase of the Catholic flock, with the approval of the Sacred Council, judge it to be necessary to propose, for the belief and acceptance of all the faithful, in accordance with the ancient and constant faith of the universal Church, the doctrine of the institution, perpetuity, and nature of the sacred Apostolic Primacy, by which the strength and solidity of the entire Church is established, and at the same time to proscribe and condemn the contrary errors, which are so harmful to the flock of Christ.
 From Sermon 4, chapter 2, of St. Leo the Great, A.D. 440, vol. 1, p. 17 of edition of Ballerini, Venice, 1753; read in the eighth lectior, on the Feast of St. Peter's Chair at Antioch, February 22.
ON THE INSTITUTION OF THE APOSTOLIC PRIMACY IN BLESSED PETER.
We therefore teach and declare that, according to the testimony of the Gospel, the primacy of jurisdiction over the universal Church of God was immediately and directly promised and given to Blessed Peter the Apostle by Christ the Lord.
For it was to Simon alone, to whom he had already said, "You shall be called Cephas" (John 1:42), that the Lord, after the confession made by him, saying, "You are the Christ, the Son of the living God", addressed these solemn words: "Blessed are you, Simon son of Jonah. For flesh and blood has not revealed this to you, but my Father, who is in heaven. And I say to you, that you are Peter, and upon this rock I will build my Church, and the gates of Hell shall not prevail against it. And I will give you the keys of the kingdom of heaven. And whatever you shall bind on earth shall be bound, even in heaven. And whatever you shall release on earth shall be released, even in heaven." (Mt 16:16-19).
And it was upon Simon alone that Jesus, after His Resurrection, bestowed the jurisdiction of Chief Pastor and Ruler over all His fold, by the words: "Feed my lambs. Feed my sheep." (John 21:15-17).
At open variance with this clear doctrine of Holy Scripture, as it has ever been understood by the Catholic Church, are the perverse opinions of those who, while they distort the form of government established by Christ the Lord in His Church, deny that Peter, in his single person, preferably to all the other Apostles, whether taken separately or together, was endowed by Christ with a true and proper primacy of jurisdiction; or of those who assert that the same primacy was not bestowed immediately and directly upon Blessed Peter himself, but upon the Church, and through the Church on Peter as her Minister.
If anyone, therefore, shall say that Blessed Peter the Apostle was not appointed the Prince of all the Apostles and the visible Head of the whole Church Militant; or that the same, directly and immediately, received from the same, Our Lord Jesus Christ, a primacy of honor only, and not of true and proper jurisdiction; let him be anathema.
ON THE PERPETUITY OF THE PRIMACY OF BLESSED PETER
IN THE ROMAN PONTIFFS.
That which the Prince of Shepherds and great Shepherd of the sheep, Jesus Christ our Lord, established in the person of the Blessed Apostle Peter to secure the perpetual welfare and lasting good of the Church, must, by the same institution, necessarily remain unceasingly in the Church; which, being founded upon the Rock, will stand firm to the end of the world. For none can doubt, and it is known to all ages, that the holy and Blessed Peter, the Prince and Chief of the Apostles, the pillar of the faith and foundation of the Catholic Church, received the keys of the kingdom from Our Lord Jesus Christ, the Savior and Redeemer of mankind, and lives, presides, and judges, to this day and always, in his successors the Bishops of the Holy See of Rome, which was founded by him, and consecrated by his blood. 
Thus, whosoever succeeds Peter in this Chair, obtains, by the institution of Christ Himself, the Primacy of Peter over the whole Church. Therefore, the disposition of truth remains, and Blessed Peter, persevering in the fortitude of the Rock that he accepted, has not relinquished the governance of the Church that he received. 
Therefore, it has always been necessary that each Church -- that is, those who are the faithful everywhere -- should agree with the Roman Church, because of the greater power of the principality that She has received, in order that, all being joined together in the unity of that Seat, from the veneration of which the rights of communion flows to all, might associate closely as members of one Head, in the compact unity of the body. 
If then, any should deny that it is by the institution of Christ the Lord and by Divine right, that Blessed Peter should have a perpetual line of successors in the Primacy over the Universal Church, or that the Roman Pontiff' is the successor of Blessed Peter in this primacy; let him be anathema.
 From the Acts (session third) of the Third General Council of Ephesus, A.D. 431, Labbe's Councils, vol. 3, p. 1154, Venice edition of 1728. See also letter of St. Peter Chrysologus to Eutyches, in life prefixed to his works, p. 13, Venice, 1750.
 From Sermon 3, chapter 3, of St. Leo the Great, vol. 1, p. 12.
 From St. Irenaeus, Against Heresies, Book 3, chapter 3, p. 175, Benedictine edition, Venice 1734; and Acts of the Synod of Aquileia, A.D. 381, Labbe's Councils , vol. 2, p. 1185, Venice, 1728.
ON THE POWER AND NATURE OF THE PRIMACY
OF THE ROMAN PONTIFF.
Therefore, resting on plain testimonies of the Sacred Writings, and adhering to the plain and express decrees both of our predecessors, the Roman Pontiffs, and of the General Councils, We renew the definition of the Ecumenical Council of Florence, in virtue of which all the faithful of Christ must believe that the Holy Apostolic See and the Roman Pontiff possesses primacy over the whole world, and that the Roman Pontiff is the successor of Blessed Peter, Prince of the Apostles, and is the true Vicar of Christ, and the Head of the whole Church, and Father and Teacher of all Christians; and that full power was given to him, in Blessed Peter, by Jesus Christ our Lord, to pasture, to rule, and to govern the Universal Church; as is also contained in the acts of the General Councils and in the Sacred Canons.
Hence we teach and declare that, by the appointment of our Lord, the Roman Church possesses a superiority of ordinary power over all other Churches, and that this power of jurisdiction of the Roman Pontiff, which is truly episcopal, is immediate; to which all, of whatever rite and dignity, both pastors and faithful, both individually and collectively, are bound, by their duty of hierarchical subordination and true obedience, to submit, not only in matters which belong to faith and morals, but also in those that appertain to the discipline and government of the Church throughout the world, so that the Church of Christ may be one flock under one Supreme Pastor through the preservation of unity both of communion and of profession of the same faith with the Roman Pontiff. This is the teaching of Catholic truth, from which no one can deviate without loss of faith and of salvation.
But so far is this power of the Supreme Pontiff from being any prejudice to the ordinary and immediate power of episcopal jurisdiction, by which Bishops, who have been set by the Holy Spirit to succeed and hold the place of the Apostles,  feed and govern, each his own flock, as true Pastors, that this their episcopal authority is really asserted, strengthened, and protected by the supreme and universal Pastor, in accordance with the words of St. Gregory the Great: "my honor is the honor of the whole Church. My honor is the firm strength of my brethren. I am truly honored, when the honor due to each and all is not withheld." 
Furthermore, from this supreme power possessed by the Roman Pontiff of governing the Universal Church, it follows that he has the right of free communication with the Pastors of the whole Church, and with their flocks, that these may be taught and ruled by him in the way of salvation. Therefore, we condemn and reject the opinions of those who hold that the communication between this supreme Head and the Pastors and their flocks can be lawfully impeded, and those who make this communication subject to the will of the secular power, so as to maintain that whatever is done by the Apostolic See, or by its authority, for the government of the Church, cannot have force or value unless it be confirmed by the assent of the secular power.
And since, by the Divine right of Apostolic primacy, the Roman Pontiff is placed over the Universal Church, We further teach and declare that he is the supreme judge of the faithful,  and that in all causes, the decision of which belongs to the Church, recourse may be had to his tribunal,  and that none may re-open the judgment of the Apostolic See, for none has greater authority, nor can anyone lawfully review its judgment.  Therefore, they stray from the right course who assert that it is lawful to appeal from the judgments of the Roman Pontiffs to an Ecumenical Council, as if to an authority higher than that of the Roman Pontiff.
If anyone, then, shall say that the Roman Pontiff has the office merely of inspection or direction, and not the full and supreme power of jurisdiction over the Universal Church, not only in things which belong to faith and morals, but also in those which relate to the discipline and government of the Church spread throughout the world; or assert that he possesses merely the principal part, and not all the fullness of this supreme power; or that this power which he enjoys is not ordinary and immediate, both over each and all the Churches and over each and all the Pastors and the faithful; let him be anathema.
 From chapter 4 of the 23rd Session of the Council of Trent, "On The Ecclesiastical Hierarchy."
 From the letters of St. Gregory the Great, book viii 30, vol. 2, p. 919, Benedictine edition, Paris, 1705.
 From a Brief of Pins VI, Super Soliditate, 28 November 1706.
 From the Acts of the Fourteenth General Council of Lyons, A.D. 1274, Labbe's, Councils, vol. 14, p. 512.
 From Letter 8 of Pope Nicholas I, A.D. 858, to the Emperor Michael, in Labbe's Councils, vol. 9, pp. 1339 and 1570
ON THE INFALLIBLE TEACHING
OF THE ROMAN PONTIFF
Moreover, this Holy See has always held, the perpetual practice of the Church confirms, and Ecumenical Councils also have declared -- especially those in which the East with the West met in the union of faith and charity -- that the supreme power of teaching is also included in the Apostolic primacy which the Roman Pontiff, as the successor of Peter, Prince of the Apostles, possesses over the whole Church. For the Fathers of the Fourth Council of Constantinople, following in the footsteps of their predecessors, gave forth this solemn profession: The first condition of salvation is to keep the rule of the true faith.
And because the sentence of our Lord Jesus Christ cannot be passed over, who said: "You are Peter, and upon this rock I will build my Church" (Mt 16:18), these things which have been said are approved by events, because in the Apostolic See the Catholic Religion and her holy and well-known doctrine has always been kept undefiled. Desiring, therefore, not, to be in the least degree separated from the faith and doctrine of that See, we hope that we may deserve to be in the one communion, which the Apostolic See preaches, in which is the entire and true solidity of the Christian religion. 
And, with the approval of the Second Council of Lyons, the Greeks professed that the Holy Roman Church enjoys supreme and full Primacy and preeminence over the whole Catholic Church, which She truly and humbly acknowledges that She has received with the plenitude of power from our Lord Himself in the person of blessed Peter, Prince or Head of the Apostles, whose successor is the Roman Pontiff; and as the Apostolic See is bound before all others to defend the truth of faith, so also if any questions regarding faith shall arise, they must be defined by its judgment. 
Finally, the Council of Florence defined:  That the Roman Pontiff is the true Vicar of Christ, and the Head of the whole Church, and the Father and Teacher of all Christians; and that to him in blessed Peter was delivered by our Lord Jesus Christ the full power of pasturing, ruling, and governing the whole Church. (John 21:15-17).
To satisfy this pastoral duty, our predecessors ever made unwearied efforts that the salutary doctrine of Christ might be propagated among all the nations of the earth, and, with equal care, they watched that it might be preserved, genuine and pure, where it had been received. Therefore, the Bishops of the whole world, at times individually, at times assembled in a synod, following the long-established custom of the Churches,  and the form of the ancient rule,  sent word to this Apostolic See especially of those dangers which sprang up in matters of faith, that the losses of faith might be most effectually repaired there, where the faith cannot fail. 
And the Roman Pontiffs, according to the exigencies of times and circumstances, sometimes assembling Ecumenical Councils, or asking for the mind of the Church scattered throughout the world, sometimes by particular Synods, sometimes using other helps which Divine Providence supplied, defined as to be held those things which, with the help of God, they had recognized as conformable with the Sacred Scriptures and Apostolic Traditions. For the Holy Spirit was not promised to the successors of Peter that by His revelation they might make known new doctrine, but that by His assistance they might inviolably keep and faithfully expound the Revelation, the Deposit of Faith, delivered through the Apostles.
And indeed, all the venerable Fathers have embraced, and the holy orthodox Doctors have venerated and followed, their Apostolic doctrine; knowing most fully that this See of holy Peter remains ever free from all blemish of error, according to the Divine promise that the Lord our Savior made to the Prince of His disciples: "But I have prayed for you, so that your faith may not fail, and so that you, once converted, may confirm your brothers." (Lk 22:32). 
This gift, then, of truth and never-failing faith was conferred by heaven upon Peter and his successors in this Chair, that they might perform their high office for the salvation of all; that the whole flock of Christ, kept away from the poisonous food of error by them, might be nourished with the pasture of heavenly doctrine; that the occasion of schism being removed, the whole Church might be kept one, and, resting on its foundation, might stand firm against the gates of Hell.
But since, in this very age in which the salutary efficacy of the Apostolic office is most of all required, not a few are found who take away from its authority, We judge it altogether necessary to assert solemnly the prerogative which the only-begotten Son of God found worthy to join with the supreme pastoral office.
Therefore, faithfully adhering to the tradition received from the beginning of the Christian faith, for the glory of God Our Savior, the exaltation of the Catholic Religion, and the salvation of Christian people, the Sacred Council approving, We teach and define that it is a divinely-revealed dogma: that the Roman Pontiff, when he speaks ex Cathedra, that is, when in discharge of the office of Pastor and Teacher of all Christians, by virtue of his supreme Apostolic authority, he defines a doctrine regarding faith or morals to be held by the Universal Church, by the divine assistance promised to him in blessed Peter, is possessed of that infallibility with which the divine Redeemer willed that His Church should be endowed for defining doctrine regarding faith or morals: and that therefore such definitions of the Roman Pontiff are irreformable of themselves, and not from the consent of the Church. 
But if anyone -- God forbid -- should presume to contradict this Our definition; let him be anathema.
Given at Rome in Public Session solemnly held in the Vatican Basilica in the year of Our Lord one thousand eight hundred and seventy, on the eighteenth day of July, in the twenty-fifth year of our Pontificate.
In conformity with the original.
JOSEPH, Bishop of S. Pollen,
Secretary to the Vatican Council.
 From the Formula of St. Hormisdas, subscribed by the Fathers of the Eighth General Council (Fourth of Constantinople), A.D. 869, Labbe's Councils, vol. 5, pp. 583, 622.
 From the Acts of the Fourteenth General Council (Second of Lyons), A.D. 1274, Labbe, vol. 14, p. 512.
 From the Acts of the Seventeenth General Council of Florence, A.D. 1438, Labbe, vol. 18, p. 526.
 From a letter of St. Cyril of Alexandria to Pope St. Celestine I, A.D. 422, vol. 4, part 2, p. 36, Paris edition of 1638.
 From a Rescript of St. Innocent I, to the Council of Milevis, A.D. 402, Labbe, vol. 3, p. 47.
 From a letter of St. Bernard to Pope Innocent II, A.D. 1130. Epist. 191, vol. 4, p. 433, Paris edition of 1742.
 See also the Acts of the Sixth General Council, A.D. 680, Labbe, vol. 7, p. 659.
 i.e. in the words used by Pope Nicholas I, note 13, and in the Synod of Quedlinburg, A.D. 1085, "it is allowed to none to revise its judgment, and to sit in judgment upon what it has judged." Labbe, vol. 12, p. 679.
[Translation by Cardinal Henry Edward Manning, Roman Catholic Archbishop of Westminster, from his book 'The Vatican Council and Its Definitions', (New York: D. & J. Sadlier, 1871).
As the Founder and Chairman of ABE Ministry, IANS profoundly apologies for every single word he has written or said that contravenes this classic infallible Doctrine. This is the Catholic Faith outside of which no man will be saved.